Question

If a kettle is not 100% efficient where does the missing energy go? And is there a way of improving the efficiency of a kettle?

Answer 1

Evidently – not to a water in the kettle: may be, it is consumed by the kettle body, or by the kitchen table, or by air etc. To make a kettle more efficient these heat leakages are to be blocked: for instance, a heating element should be located in the middle of the water and better thermos isolation of a kettle body are to be used.